This invention relates generally to improvements in heat exchangers of the so-called plate-fin type. More specifically, this invention relates to a plate-fin heat exchanger including an improved and simplified header construction.
Plate-fin heat exchangers in general are known in the art for use in transferring heat energy from one working fluid to another. In one common form, such heat exchangers typically comprise a plurality of relatively thin divider plates arranged in an alternating stack with a plurality of extended surface heat transfer elements, such as corrugated fins and the like. The extended surface heat transfer elements, or fins, are commonly turned alternately at right angles with respect to each other to define two closely adjacent fluid flow paths for passage of the two working fluids at right angles to each other. This construction is commonly known as a cross-flow heat exchanger and includes appropriate header bars along side margins of the stack to isolate the two working fluids from one another. When the stack is assembled, the various components thereof are commonly secured together preferably in a single bonding operation, such as by brazing or the like.
Plate-fin heat exchangers further require some type of manifold or header structure for guiding at least one of the working fluids for ingress and egress with respect to its associated flow path through the heat exchanger core in isolation from the other working fluid. For example, when the heat exchanger is used to transfer heat energy between a liquid and a gas, the liquid is normally supplied through an appropriate inlet conduit to an inlet header mechanically connected to the heat exchanger core to guide the liquid for flow into and through one of the flow paths in the core in heat transfer relation with the gas which typically flows freely without headers through the other core flow path. An outlet header mechanically connected to the heat exchanger core collects the liquid discharged from the one flow path for passage away from the heat exchanger through an appropriate outlet conduit.
The inlet and outlet headers have been the subject of significant engineering activity in an effort to simplify heat exchanger design and reduce cost of manufacture while increasing the versatility and operating life of the heat exchanger. In this regard, the inlet and outlet headers conventionally have constituted mechanical structures independent of the heat exchanger core adapted for attachment to the core subsequent to bonding of the various core-forming components. While such separate header structures advantageously permit the headers to include fluid fittings oriented in a selected direction for convenient connection to the associated inlet and outlet fluid conduits, they increase the mechanical complexity of the heat exchanger as well as the cost of manufacture by requiring more than one bonding operation.
Other heat exchanger designs have been proposed which attempt to incorporate inlet and outlet headers directly into the heat exchanger core thereby permitting the core and the headers to be assembled in a single cost-efficient bonding operation. However, these designs have not included inlet and outlet fluid fittings adapted for orientation in any selected direction for connection to the associated inlet and outlet fluid conduits. Instead, such designs have required the subsequent addition of appropriately directed fluid fittings which are attached to the headers by a subsequent bonding operation.
The present invention overcomes the problems and disadvantages of the prior art by providing an improved and simplified heat exchanger construction having inlet and outlet headers incorporated integrally with a heat exchanger core wherein each header includes a fluid fitting adapted for orientation in a selected direction prior to connection of the heat exchanger components in a single bonding operation.